JP4976292B2 - Heterocyclic compound and organic electroluminescence device using the same - Google Patents

Description

  The present invention relates to a condensed heterocyclic compound having a substituted amino group and an organic electroluminescence device using the same.

  The development of electroluminescent (hereinafter referred to as organic EL) devices using organic materials has been optimized for the purpose of improving the efficiency of charge injection from the electrodes. The hole transport layer made of aromatic diamine and 8-hydroxyquinoline The development of a device in which a light emitting layer made of an aluminum complex is provided as a thin film between the electrodes has led to a significant improvement in light emission efficiency compared to conventional devices using single crystals such as anthracene. It has been promoted with the aim of putting it into practical use for high-performance flat panels, which are characterized by high-speed response.

  On the other hand, many devices, including devices provided with a hole transport layer made of aromatic diamine and a light emitting layer made of aluminum complex of 8-hydroxyquinoline, used fluorescent light emission. That is, if light emission from a triplet excited state is used, an efficiency improvement of about 3 to 4 times is expected as compared with a conventional device using fluorescence (singlet). Recently, many phosphorescent dopants have been developed for this purpose.

Special Table 2003-515897 JP 2001-313178 A JP 2002-352957 A Nature, 395, 151, 1998 Appl. Phys. Lett., 75, 4 pages, 1999

  Non-Patent Document 1 reports that high-efficiency red light emission is possible by using a platinum complex (PtOEP). Thereafter, in Non-Patent Document 2, the emission layer is doped with tris (2-phenylpyridine) iridium (Ir (ppy) 3), which is an iridium complex, so that the efficiency of green emission is greatly improved. Furthermore, it has been reported that these iridium complexes exhibit extremely high luminous efficiency even when the device structure is further simplified by optimizing the light emitting layer.

  In order to apply an organic EL element to a display element such as a flat panel display, it is necessary to improve the light emission efficiency of the element and at the same time to ensure sufficient stability during driving. However, in the high-efficiency organic electroluminescent device using phosphorescent molecules described in Non-Patent Document 2, the driving stability is insufficient in practice.

  In Non-Patent Document 2, 4,4′-bis (9-carbazolyl) biphenyl (CBP) or 3-phenyl-4- (1′-naphthyl) -5-phenyl-1,2,4-triazole (CBP) is used as the light-emitting layer. TAZ) and phenanthroline derivatives as hole blocking layers. Further, in Patent Document 1 and Patent Document 2, CBP is preferred as a host material.

  However, when CBP is used, CBP tends to flow holes easily and electrons do not flow easily, the charge balance in the light emitting layer is lost, and excess holes flow out to the electron transport side, resulting in Ir (ppy) There is a problem that the luminous efficiency from 3 is lowered. On the other hand, TAZ has a characteristic that electrons easily flow and holes do not easily flow, so that the light emitting region is on the hole transport layer side. In this case, the hole transport material used affects the light emission efficiency from Ir (ppy) 3. For example, 4,4'-bis (N- (1-naphthyl) -N-phenylamino) biphenyl (NPB), which is most often used as a hole transport layer in terms of high performance, high reliability, and long life When it is used, there is a problem that energy transition occurs from Ir (ppy) 3 to NPB and the luminous efficiency is lowered.

  As a solution to the above, no energy transition occurs from Ir (ppy) 3 such as 4,4'-bis (N, N '-(3-toluyl) amino) -3, 3'-dimethylbiphenyl (HMTPD) Although means using the material as the hole transport layer can be considered, it cannot be said that it is excellent in terms of durability.

  Furthermore, compounds such as CBP and TAZ are easily crystallized and aggregated to deteriorate the shape of the thin film, and Tg is difficult to observe due to its high crystallinity. Such an unstable thin film shape in the light emitting layer has an adverse effect of shortening the driving life of the device and lowering the heat resistance. For the reasons described above, organic electroluminescence devices using phosphorescence have a serious problem in driving stability of the devices.

  In order to apply the organic EL element to a display element such as a flat panel display, it is necessary to improve the light emission efficiency of the element and at the same time to ensure sufficient stability during driving. An object of this invention is to provide the organic EL element which has high efficiency and high drive stability, and a compound suitable for it in view of the said present condition.

  The present inventors have found that a heterocyclic compound represented by the following general formula (I) has excellent charge (electron / hole) transportability and high triplet excitation energy. In addition, the present inventors have found that the derivatives have good thin film stability and thermal stability and completed the present invention.

式中、Ｘ₁及びＸ₂は独立にＯ、Ｓ又はＮ-Ｒを示す。Ｒは水素、置換若しくは未置換アルキル基又は置換若しくは未置換アリール基を示す。Ar₁、Ar₂、Ar₃及びAr₄は独立に置換又は未置換のアリール基を示し、Ar₁とAr₂、及びAr₃とAr₄は結合している窒素と共に含窒素複素環を形成してもよい。ｍ及びｎは独立に１又は２を示す。
The present invention has a structure represented by the following formula (I), and an organic electroluminescent device comprising an organic layer containing the following general formula (II) or (III) you express heterocyclic compound.

In the formula, X ₁ and X ₂ independently represent O, S or N—R. R represents hydrogen, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ independently represent a substituted or unsubstituted aryl group, and Ar ₁ and Ar ₂ , and Ar ₃ and Ar ₄ form a nitrogen-containing heterocycle together with the nitrogen to which they are bonded. May be. m and n independently represent 1 or 2.

式中、-NAr ₁ Ar ₂ 及び-NAr ₃ Ar ₄ は独立に未置換、又は低級アルキル基、低級アルコキシ基、炭素数４〜１０のアリール基若しくは炭素数４〜１０のアリールオキシ基で置換された置換Ｎ-カルバゾリル基である。但し、-NAr ₁ Ar ₂ 及び-NAr ₃ Ar ₄ の置換位置が2,8位でである場合を除く。また、上記アリール基は炭素環式芳香族基と複素環式芳香族基の両者を意味する。
In the heterocyclic compound represented by the general formula (I), preferred heterocyclic compounds are exemplified below.

In the formula, —NAr ₁ Ar ₂ and —NAr ₃ Ar ₄ are independently unsubstituted or substituted with a lower alkyl group, a lower alkoxy group, an aryl group having 4 to 10 carbon atoms, or an aryloxy group having 4 to 10 carbon atoms. Or a substituted N-carbazolyl group. However, the case where the substitution position of -NAr ₁ Ar ₂ and -NAr ₃ Ar _{4 is} the _2nd and 8th positions is excluded. The aryl group means both a carbocyclic aromatic group and a heterocyclic aromatic group.

In the general formulas (I) to (IV), preferable Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ are exemplified below.
Phenyl group, naphthyl group, phenanthryl group, pyridinyl group, pyrazyl group, pyrimidyl group substituted by unsubstituted or lower alkyl group, lower alkoxy group, aryl group having 4 to 10 carbon atoms or aryloxy group having 4 to 10 carbon atoms , An imidazolyl group, a thienyl group or a furyl group. Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ may be the same as or different from each other.
Further, preferred examples of —NAr ₁ Ar ₂ and —NAr ₃ Ar ₄ in the case where a nitrogen-containing heterocyclic ring is formed with nitrogen to which Ar ₁ and Ar ₂ and Ar ₃ and Ar ₄ are bonded are shown below.
N-carbazolyl group, N-phenoxazinyl group, N-phenothiazinyl group or N-substituted by unsubstituted or lower alkyl group, lower alkoxy group, aryl group having 4 to 10 carbon atoms or aryloxy group having 4 to 10 carbon atoms -Carborinyl group. -NAr ₁ Ar ₂ and -NAr ₃ Ar ₄ may be the same as or different from each other.

  Moreover, this invention is an organic electroluminescent element which has an organic layer containing the said heterocyclic compound. As this organic layer, a light emitting layer, a hole transport layer, or a hole injection layer is preferably exemplified. Furthermore, it is preferable that this organic layer is a light emitting layer containing a phosphorescent dopant or a hole transport layer in contact with the phosphorescent light emitting layer.

In the general formulas (I) to (IV), the unsubstituted aryl group is, for example, a carbocyclic aromatic group such as a phenyl group, a naphthyl group, an anthryl group, or a phenanthryl group, for example, a furyl group, a thienyl group, It means a heterocyclic aromatic group such as a pyridyl group. Preferably, it is a carbocyclic aromatic group having 6 to 18 carbon atoms or a heterocyclic aromatic group having 4 to 17 carbon atoms and 1 to 4 heteroatoms. More preferably, it is a C6-C16 carbocyclic aromatic group or a C4-C14 heterocyclic aromatic group. The number of aryl groups is 1-4, preferably 1-3, and may or may not be condensed. When used as a light emitting layer containing a phosphorescent dopant or a hole transporting layer in contact with the phosphorescent light emitting layer, Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ are 1 to 3 non-condensed aryl groups. Is preferred.

Preferred examples of the substituted aryl group include an alkyl group, an alkoxy group, an aryl group having 4 to 12 carbon atoms, or a carbocyclic aromatic group having 6 to 16 carbon atoms substituted with an aryloxy group having 4 to 12 carbon atoms, or It is a C4-C14 heterocyclic aromatic group. In the case of a heterocyclic aromatic group, examples of the hetero atom include S, O and the like in addition to N, and the number is preferably in the range of 1 to 4 in total. Ar ₁ and Ar ₂ and Ar ₃ and Ar ₄ may form a nitrogen-containing heterocycle together with the bonded nitrogen. In this case, —NAr ₁ Ar ₂ and —NAr ₃ Ar ₄ represent a substituted or unsubstituted N-carbazolyl group, N-phenoxazinyl group, N-phenothiazinyl group, N- • carbolinyl group, and the like.

  Specific examples of the unsubstituted aryl group include phenyl group, naphthyl group, phenanthryl group, indenyl group, azulenyl group, heptalenyl group, acenaphthylenyl group, phenalenyl group, fluorenyl group, anthryl group, biphenylenyl group, triphenylenyl group, tetraphenylyl group. Nyl group, pyrenyl group, chrysenyl group, picenyl group, perylenyl group, pentaphenyl group, pentacenyl group, hexaphenyl group, hexacenyl group, rubicenyl group, coronyl group, trinaphthylenyl group, heptaphenyl group, heptacenyl group, pyrantrenyl group, and oberenyl group , Furyl group, thienyl group, pyridyl group, carbazolyl group, thiantenyl group, pyranyl group, isobenzofuranyl group, chromenyl group, gisanthenyl group, phenoxatinyl group, pyrrolyl group, imidazolyl group, pyra Ryl, isothiazolyl, isoxazolyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolizinyl, isoindolyl, purinyl, indolyl, quinolyl, isoquinolyl, acridinyl, phenanthrolinyl, phthalazinyl, naphthyridinyl Quinoxalinyl group, quinazolinyl group, phenanthridinyl group, perimidinyl group, phenanthrolinyl group, phenazinyl group, flazanyl group and the like. Preferably, phenyl group, naphthyl group, phenanthryl group, indenyl group, fluorenyl group, anthryl group, pyrenyl group, perylenyl group, pentaphenyl group, coronyl group, furyl group, thienyl group, pyridyl group, carbazolyl group, pyranyl group, pyrrolyl group Group, imidazolyl group, pyrazolyl group, isothiazolyl group, isoxazolyl group, pyrimidinyl group, indolizinyl group, indolyl group, quinolyl group, isoquinolyl group, acridinyl group, phenanthrolinyl group, quinoxalinyl group, quinazolinyl group, phenazinyl group, etc. .

  A preferable unsubstituted alkyl group is an alkyl group having 1 to 6 carbon atoms. Specific examples include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, stearyl and the like.

  Specific examples of the substituent of the substituted aryl group and the substituted alkyl group are preferably nitro group, cyano group, alkyl group, aralkyl group, aralkyloxy group, alkoxy group, aryl group and aryloxy group. Specifically, as the alkyl group, methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, stearyl group, etc. There is. Examples of the aralkyl group include a 2-phenylisopropyl group, a benzyl group, and a triphenylmethyl group. Alkoxy groups include methoxy, ethoxy, propoxy, n-butoxy, sec-butoxy, tert-butoxy, pentyloxy, hexyloxy, n-octyloxy, tert-octyloxy, stearyl There are oxy groups. Examples of the aralkyloxy group include a benzyloxy group. As the aryl group, phenyl group, biphenyl group, naphthyl group, phenanthryl group, indenyl group, naphthyl group, azulenyl group, heptalenyl group, acenaphthylenyl group, phenalenyl group, fluorenyl group, anthryl group, biphenylenyl group triphenylenyl group, tetraphenylenyl group , Pyrenyl group, chrysenyl group, picenyl group, perylenyl group, pentaphenyl group, pentacenyl group, hexaphenyl group, hexacenyl group, rubicenyl group, coronyl group, trinaphthylenyl group, heptaphenyl group, heptaenyl group, pyranthrenyl group, ovenyl group, furyl Group, thienyl group, pyridyl group, carbazolyl group, thiantenyl group, pyranyl group, isobenzofuranyl group, chromenyl group, gysanthenyl group, phenoxatinyl group, pyrrolyl group, imidazolyl group Pyrazolyl group, isothiazolyl group, isoxazolyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, indolizinyl group, isoindolyl group, purinyl group, indolyl group, quinolyl group, isoquinolyl group, acridinyl group, phenanthrolinyl group, phthalazinyl group, naphthyridinyl group , Quinoxalinyl group, quinazolinyl group, phenanthridinyl group, perimidinyl group, phenanthrolinyl group, phenazinyl group, furazanyl group, 4-methylbiphenyl group, 3-nitrophenyl group, 4-cyanophenyl group, o-, m -And p-methoxyphenyl groups, o-, m-, and p-tolyl groups, o-, m-, and p-cumenyl groups, mesityl groups, 4-phenoxyphenyl groups, 5-methylnaphthyl groups, etc. . The aryloxy group includes an aryloxy group of the above aryl group. These substituents may be bonded together at adjacent substituents to form a new saturated ring or aromatic ring.

Representative examples of the heterocyclic compound represented by the general formula (1) are illustrated in Tables 1 to 4 below, but are not limited to these representative examples. Here, compounds 12, 13 and 27 are heterocyclic compounds (also referred to as heterocyclic compounds of the present invention) used in the organic electroluminescence device of the present invention. Also in the examples, it is understood that Examples 1, 6, 7 and 10 using the above compounds are Examples, and the others are Reference Examples.

  As one of the methods for synthesizing the heterocyclic compound represented by the general formula (1) of the present invention, the corresponding amine derivative and the corresponding aryl halide can be used in an organic solvent or without solvent in the presence of a base and a catalyst. It can be obtained by reacting at a temperature of about 100 to 200 ° C. for about 1 to 50 hours in a nitrogen atmosphere. Examples of the halogen atom of the aryl halide include chlorine, bromine, iodine and the like. Examples of the base used include inorganic bases such as potassium carbonate, sodium carbonate, lithium hydroxide, sodium hydroxide, sodium tert-butoxide and potassium tert-butoxide, and organic bases such as pyridine, picoline and triethylamine. Catalysts include copper powders, copper oxides, copper halides, copper sulfates and other copper catalysts, or palladium sources such as palladium acetate and bis (dibenzylideneacetone) palladium and ligands such as tri-tert-butylphosphine. The palladium complex catalyst formed is mentioned. The solvent should just be a thing which can melt | dissolve a raw material and can make it react. Examples thereof include solvents such as toluene, xylene, tetralin, quinoline, nitrobenzene, dimethyl sulfoxide, N, N-dimethylformamide and the like.

  After completion of the reaction, water is added to separate the organic layer, which is concentrated, washed with a low boiling point solvent such as ethyl acetate, and dried under reduced pressure to obtain the compound of the present invention. When the heterocyclic compound of the present invention is used as an organic EL material, it is preferably further purified by sublimation.

Next, the organic EL element of the present invention will be described.
There are various modes as the structure of the organic EL device of the present invention. Basically, the organic EL element-containing organic layer is sandwiched between a pair of electrodes (a cathode and an anode). The heterocyclic compound can be used alone as a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, an electron injection layer, or an electron transport layer. A hole injection material, a hole transport material, a hole blocking material, a light emitting material, an electron injection material, an electron transport material, or the like can be added. In particular, when the heterocyclic compound is used as a light emitting layer, by adding another light emitting material to the light emitting layer, light of different wavelengths can be generated or the light emission efficiency can be improved. In addition, hole injection material, hole transport material, light emitting material, hole blocking material, electron injection material or electron transport material, hole injection layer, hole transport layer, light emitting layer, hole blocking layer, electron injection It can also be laminated on a layer containing the heterocyclic compound as a layer or an electron transport layer.

As a specific configuration,
1 Anode / organic light emitting layer / cathode
2 Anode / hole transport layer / organic light emitting layer / cathode
3 Anode / hole transport layer / organic light emitting layer / hole blocking layer / cathode
4 Anode / Hole injection layer / Hole transport layer / Organic light emitting layer / Cathode
5 Anode / Hole injection layer / Hole transport layer / Organic light emitting layer / Hole blocking layer / Cathode
6 Anode / organic light emitting layer / electron transport layer / cathode
7 Anode / organic light emitting layer / electron transport layer / electron injection layer / cathode
8 Anode / Organic light emitting layer / Hole blocking layer / Electron transport layer / Electron injection layer / Cathode
9 Anode / Hole transport layer / Organic light emitting layer / Hole blocking layer / Electron transport layer / Cathode
10 Anode / Hole injection layer / Hole transport layer / Organic light emitting layer / Electron transport layer / Cathode
11 Anode / Hole injection layer / Hole transport layer / Organic light emitting layer / Electron transport layer / Hole blocking layer / Cathode
12 Anode / hole injection layer / hole transport layer / organic light emitting layer / electron transport layer / electron injection layer / cathode
13 A laminated structure of anode / hole injection layer / hole transport layer / organic light emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode. In these cases, the hole injection layer, the electron injection layer, and the hole blocking layer are not necessarily required, but the light emission efficiency can be improved by providing these layers.

  When the heterocyclic compound of the present invention is applied to a light emitting layer, it is particularly suitable for a light emitting layer containing a phosphorescent light emitting dopant. When used in a light-emitting layer, the compound of the present invention is preferably the main component in the light-emitting layer, and in particular, this light-emitting layer uses the heterocyclic compound as a host material and the host material is doped with a phosphorescent dopant. It is desirable that the light emitting layer be formed.

  Examples of the phosphorescent dopant material include those containing an organometallic complex containing at least one metal selected from ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum and gold. Such organometallic complexes are known in the above-mentioned patent documents and the like, and these can be selected and used.

  Preferable phosphorescent dopants include complexes such as Ir (ppy) 3 having a noble metal element such as Ir as a central metal, complexes such as Ir (bt) 2 · acac3, and complexes such as PtOEt3. Specific examples of these complexes are shown below, but are not limited to the following compounds.

  When the phosphorescent dopant is contained in the light emitting layer, the amount is preferably in the range of 1 to 10% by weight.

The schematic cross section which showed an example of the organic EL element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Electron transport layer 7 Cathode

  Next, the structure of the organic EL element of the present invention will be described with reference to the drawings. However, the structure of the organic EL element of the present invention is not limited to the illustrated one.

  FIG. 1 is a cross-sectional view schematically showing a general organic EL device, in which 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a hole transport layer, 5 is a light emitting layer, and 6 is an electron. Each of the transport layers 7 represents a cathode. As for an organic EL element, it is desirable to make a board | substrate, an anode, a positive hole transport layer, a light emitting layer, an electron carrying layer, and a cathode into an essential layer. In this case, the hole injection layer 3 and the like can be omitted, and other layers such as a hole blocking layer may be provided as necessary.

  In addition, it is also possible to laminate | stack the cathode 7, the electron carrying layer 6, the light emitting layer 5, the positive hole transport layer 4, and the anode 2 in order on the board | substrate 1 in the structure contrary to FIG. 1, and at least one is transparent. It is also possible to provide the organic EL element of the present invention between two highly functional substrates.

  The present invention can be applied to any of an organic EL element having a single element, an element having a structure arranged in an array, and a structure having an anode and a cathode arranged in an XY matrix.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, it is not limited to these Examples. Compound 1, Compound 3, Compound 8, Compound 9, Compound 12, and Compound 27 were synthesized by the route shown below. The compound numbers correspond to the numbers given to the compounds in Tables 1 to 4.

Synthesis example 1
Synthesis of 2,7-dinitrodibenzodioxin 60 g (0.326 mol) of dibenzodioxin was added to 1600 ml of acetic acid, and 280 ml of fuming nitric acid was added dropwise over 1 h while stirring at room temperature. After completion of the dropwise addition, stirring was continued for 2 hours, and the resulting precipitate was collected by filtration. After reslurry with methanol, it was dried under reduced pressure to obtain 85.7 g (0.313 mol, yield 96.0%) of 2,7-dinitrodibenzodioxin. The purity of the obtained product was 96.5 area% (HPLC, 254 nm).

Synthesis example 2
Synthesis of 2,7-diaminodibenzodioxin Add 69.7 g (0.254 mol) of 2,7-dinitrodibenzodioxin and 22.2 g of 10% palladium carbon to a mixed solution of 1200 ml of anisole and 800 ml of THF, and hydrogen for 8 h under stirring at room temperature. Gas was aerated. 10% palladium carbon was removed by filtration, a precipitate containing 10% palladium carbon was further collected by filtration, and the filtered product was rinsed with THF. The rinse solution was concentrated and dried under reduced pressure to obtain 25.0 g (0.117 mol, yield 46.0%) of 2,7-diaminodibenzodioxin. The purity of the obtained product was 98.1% (HPLC, 254 nm).

Synthesis example 3
Synthesis of 2,7-bis (acetylamino) dibenzodioxin To a mixed solution of 900 ml of toluene and 900 ml of THF, add 50.0 g (0.233 mol) of 2,7-diaminodibenzodioxin and 55.3 g (0.699 mol) of pyridine at room temperature. Under stirring, 59.5 g (0.583 mol) of acetic anhydride was added dropwise over 10 min. After dropping, the mixture was stirred overnight and the precipitate was collected by filtration. After reslurrying with toluene (250 ml × 2), 57.0 g (0.191 mol, yield 82.0%) of 2,7-bis (acetylamino) dibenzodioxin was obtained by drying under reduced pressure. The purity of the obtained product was 99.3 area% (HPLC, 254 nm).

Synthesis example 4
Synthesis of 2,7-bis (N-phenylacetylamino) dibenzodioxin
2,7-bis (acetylamino) dibenzodioxin 34.3 g (0.115 mol), iodobenzene 96.4 g (0.576 mol), copper (I) iodide 48.2 g (0.253 mol), potassium carbonate 63.6 g (0.460 mol), and Quinoline 1500 ml slurry solution was heated and stirred at 170 ° C. for 48 h. After cooling to room temperature, 500 ml of methylene chloride and 500 ml of water were added, and the precipitate was separated by filtration. The filtrate was further added with 500 ml of water and separated into oil and water. The organic layer was concentrated and then dried under reduced pressure to obtain 79.4 g of a crude product. This was used in the next reaction without purification.

Synthesis example 5
Synthesis of 2,7-bis (phenylamino) dibenzodioxin 79.4 g of the diacetamide compound obtained in Synthesis Example 4 was added to a mixed solution of 500 g of methanol and 100 g of a 24% aqueous sodium hydroxide solution, and the mixture was heated to reflux for 20 hours. After cooling to room temperature, 1000 ml of water was added and the precipitate was collected by filtration. After rinsing with water, 44.3 g of 2,7-bis (phenylamino) dibenzodioxin was obtained by drying under reduced pressure. The obtained crude product was purified by reslurry with methanol. Yield 31.8 g (0.087 mol, yield 75.7% (2steps)), purity 98.4 area% (HPLC, 254 nm).

Synthesis Example 6
Synthesis of 2,7-bis (N-3-pyridylacetylamino) dibenzodioxin
2,7-bis (acetylamino) dibenzodioxin 7.0 g (0.023 mol), 3-iodopyridine 12.0 g (0.059 mol), copper (I) iodide 9.8 g (0.051 mol), potassium carbonate 12.9 g (0.093 mol) The slurry solution of 230 ml of quinoline was stirred with heating at 170 ° C. for 72 hours. After cooling to room temperature, 100 ml of methylene chloride and 100 ml of water were added, and the precipitate was separated by filtration. The filtrate was further added with 100 ml of water and separated into oil and water. The organic layer was concentrated and then dried under reduced pressure to obtain 23.5 g of a crude product. This was used in the next reaction without purification.

Synthesis example 7
Synthesis of 2,7-bis (3-pyridylamino) dibenzodioxin 23.5 g of the diacetamide compound obtained in Synthesis Example 6 was added to a mixed solution of 75 g of methanol and 35.6 g of 24% aqueous sodium hydroxide, and the mixture was heated to reflux for 120 h. . After cooling to room temperature, 200 ml of water was added and the precipitate was collected by filtration. After rinsing with water, 8.51 g of 2,7-bis (3-pyridylamino) dibenzodioxin was obtained by drying under reduced pressure. The resulting crude product was purified by heat reslurry with THF followed by heat reslurry with methanol. Yield 8.39 g (0.023 mol, Yield 97.3% (2steps)), Purity 95.7 area% (HPLC, 254 nm)

Synthesis Example 8
Synthesis of 2,7-diacetylthianthrene Cool a mixed solution of 34.3 g (0.158 mol) of thianthrene, 86.0 g (0.645 mol) of aluminum chloride and 160 ml of dichloromethane to 10 ° C or less, and 90 ml of acetyl chloride at the same temperature ( 1.27 mol) was added dropwise over 1 h. After completion of dropping, the mixture was returned to room temperature and stirred overnight. The reaction mixture was gradually poured into cold water, and the resulting tan precipitate was collected by filtration. Further, the methylene chloride layer in the filtrate mother liquor was concentrated, and a yellowish brown precipitate was collected by filtration. Acetone was added to these filtrates, acetone insolubles were filtered off, and the filtrate mother liquor was concentrated to obtain a crude product. This was recrystallized from toluene to obtain 2,7-diacetylthianthrene. Yield 24.6 g (0.082 mol, Yield 52%), Purity 95.6 area% (HPLC, 254 nm)

Synthesis Example 9
Synthesis of 2,7-bis (1-hydroxyiminoethyl) thianthrene
To a solution of 11.3 g (0.034 mol) of 2,7-diacetylthianthrene in ethanol (550 ml) was added 30 ml of a 50% hydroxyamine aqueous solution, and the mixture was heated and stirred at 80 ° C. for 7 hours. The reaction mixture was cooled to room temperature, poured into water (3 L), and acidified (pH 3-4) with hydrochloric acid. After extraction with ethyl acetate, the organic layer was concentrated to obtain 11.86 g of a crude product. In addition to ethyl acetate, 2,7-bis (1-hydroxyiminoethyl) thianthrene, which is insoluble, was collected by filtration. Yield 5.93 g (0.018 mol, Yield 53%), Purity 96.0 area% (HPLC, 254 nm)

Synthesis Example 10
Synthesis of 2,7-bis (acetylamino) thianthrene To 264 g of polyphosphoric acid, 15.1 g (0.0455 mol) of 2,7-bis (1-hydroxyiminoethyl) thianthrene was added, and the mixture was heated and stirred at 110 ° C for 40 min. . The reaction mixture was cooled to room temperature and poured into 5 L of stirred water. The resulting precipitate was collected by filtration, dissolved in 500 ml of methanol, and the insoluble matter was separated by filtration. The filtered mother liquor was poured into 5 L of water, and 2,7-bis (acetylamino) thianthrene, which is insoluble, was collected by filtration. Yield 9.23 g (0.028 mol, 61% yield), purity 80.8 area% (HPLC, 254 nm)

Synthesis Example 11
Synthesis of 2,7-diaminothianthrene
A mixed solution of 5.75 g (0.0174 mol) of 2,7-bis (acetylamino) thianthrene, 12 ml of concentrated hydrochloric acid, and 140 ml of ethanol was heated to reflux for 6 hours. The mixture was cooled to room temperature and the precipitate was collected by filtration. This was added to a mixed solution of concentrated hydrochloric acid (13.5 ml) and water (355 ml), and the insoluble material was filtered off. The filtered mother liquor was poured into an aqueous sodium hydroxide solution, and 2,7-diaminothianthrene precipitated was collected by filtration. Yield 3.7 g (0.0158 mol, 91% yield), purity 88.2 area% (HPLC, 254 nm)

Example 1
Synthesis of 2,7-bis (9-carbazolyl) dibenzodioxin (compound 12) In a solution of 0.79 g (3.5 mmol) palladium (II) acetate in xylene (50 ml), 2.84 g (11.2 mmol) tri tert-butylphosphine And stirred with heating at 80 ° C. for 30 min. 7.57 g (0.0352 mol) of 2,7-diaminodibenzodioxin, 22.0 g (0.0705 mol) of 2,2'-dibromobiphenyl and 28.41 g (0.296 mol) of tert-butoxy sodium heated to 80 ° C. (500 ml) The solution was fed into the solution. Thereafter, the temperature was raised to 125 ° C., and the mixture was heated and stirred at the same temperature for 5 hours. After cooling to room temperature, 250 ml of water was added. After separating the oil and water, the aqueous layer was washed with 250 ml of toluene, the organic layer was mixed, concentrated and dried under reduced pressure to obtain 14.8 g of a crude product. After reslurrying with heating with ethyl acetate, the residue was dried under reduced pressure to obtain 4.60 g (0.00894 mol, yield 25.4%) of 2,7-bis (9-carbazolyl) dibenzodioxin. The purity of the obtained product was 99.2 area% (HPLC, 254 nm). Further sublimation purification was performed. FD-MS, m / z 514 [M] +, mp348 ° C, glass transition point (Tg) 118 ° C.

Example 2
Synthesis of 2,7-bis (N-3-biphenylyl-N-phenylamino) dibenzodioxin (Compound 1) Tri-tert-butyl palladium (II) acetate in 0.28 g (1.24 mmol) in xylene (20 ml) 0.96 g (4.28 mmol) of phosphine was added, and the mixture was stirred with heating at 80 ° C. for 30 min. This solution was heated to 80 ° C with 2,7-bis (phenylamino) dibenzodioxin 9.0 g (0.025 mol), 3-bromobiphenyl 14.3 g (0.061 mol), and tert-butoxy sodium 9.53 g (0.099 mol) xylene. (200 ml) The solution was fed into the solution. Thereafter, the temperature was raised to 140 ° C., and the mixture was heated and stirred at the same temperature for 6 hours. After cooling to room temperature, 100 ml of water was added, and the precipitate was removed by filtration. The mother liquor was separated into oil and water, and the water tank was washed with 100 ml of toluene, and then the organic layer was mixed, concentrated and dried under reduced pressure to obtain 17.9 g of a crude product. 2,7-bis (N-3-biphenylyl-N-phenylamino) dibenzodioxin is obtained by treatment with activated carbon, crystallization with THF / methanol solvent, and subsequent purification with heated reslurry with ethyl acetate. 11.7 g (0.017 mol, yield 69.7%) was obtained. The purity of the obtained product was 99.0 area% (HPLC, 254 nm). Further sublimation purification was performed. FD-MS, m / z 671 [M] +, mp 232 ℃, Tg 85 ℃.

Example 3
Synthesis of 2,7-bis (N-3-biphenylyl-N-3-pyridylamino) dibenzodioxin (compound 3) In a solution of palladium (II) acetate (0.28 g, 1.24 mmol) in xylene (20 ml), tri-tert- Butylphosphine 0.96 g (4.28 mmol) was added, and the mixture was stirred with heating at 80 ° C. for 30 min. This solution was heated to 80 ° C. with 2,7-bis (3-pyridylamino) dibenzodioxin 9.0 g (0.024 mol), 3-bromobiphenyl 14.2 g (0.061 mol) and tert-butoxy sodium 9.53 g (0.099 mol). The solution was transferred into a xylene (200 ml) solution. Thereafter, the temperature was raised to 140 ° C., and the mixture was heated and stirred at the same temperature for 22 hours. After cooling to room temperature, 200 ml of water was added, and the precipitate was removed by filtration. The mother liquor was separated into oil and water, and the water tank was washed with 200 ml of toluene, and then the organic layer was mixed, concentrated and dried under reduced pressure to obtain 15.2 g of a crude product. The residue was subjected to silica gel column chromatography to obtain 5.25 g (0.0078 mol, yield 32.5%) of 2,7-bis (N-3-biphenylyl-N-3-pyridylamino) dibenzodioxin. The purity of the obtained product was 95.0 area% (HPL C, 254 nm). Further sublimation purification was performed. Neither FD-MS, m / z 672 [M] +, melting point, or glass transition point was observed.

Example 4
Synthesis of 2,7-bis (N-1-naphthyl-N-phenylamino) dibenzodioxin (compound 8) Tri (tert-butyl) in a solution of palladium (II) acetate 0.161 g (0.715 mmol) in xylene (20 ml) Phosphine 0.58 g (2.86 mmol) was added, and the mixture was heated with stirring at 80 ° C. for 30 min. A solution of 5.24 g (0.0143 mol) of 2,7-bis (phenylamino) dibenzodioxine, 7.41 g (0.0358 mol) of 1-bromonaphthalene and 5.77 g (0.06 mol) of tert-butoxy sodium heated to 80 ° C. The solution was transferred into a xylene (260 ml) solution. Thereafter, the temperature was raised to 135 ° C., and the mixture was heated and stirred at the same temperature for 4 hours. After cooling to room temperature, 200 ml of water was added. After separating the oil and water, and washing the aqueous layer with 200 ml of toluene, the organic layer was mixed, concentrated and dried under reduced pressure to obtain 9.5 g of a crude product. After reslurrying by heating with ethyl acetate, 3.40 g (0.0055 mol, yield 38.5%) of 2,7-bis (N-1-naphthyl-N-phenylamino) dibenzodioxin was obtained by drying under reduced pressure. The purity of the obtained product was 98.3 area% (HPLC, 254 nm). Further sublimation purification was performed. FD-MS, m / z 618 [M] +, mp 315 ° C, Tg 103 ° C.

Example 5
Synthesis of 2,7-bis (N-9-phenanthryl-N-phenylamino) dibenzodioxin (Compound 9) Tri-tert-butyl in a solution of palladium (II) acetate 0.12 g (0.55 mmol) in xylene (10 ml) 0.445 g (2.2 mmol) of phosphine was added, and the mixture was stirred with heating at 80 ° C. for 30 min. This solution was heated to 80 ° C with 2,7-bis (phenylamino) dibenzodioxin 4.03 g (0.011 mol), 9-bromophenanthrene 7.07 g (0.0275 mol) and 4.44 g (0.0462 mol) tert-butoxy sodium xylene. (200 ml) The solution was fed into the solution. Thereafter, the temperature was raised to 1 35 ° C., and the mixture was stirred at the same temperature for 3 hours. After cooling to room temperature, 150 ml of water was added, and the precipitate was removed by filtration. The mother liquor was separated into oil and water, and the water tank was washed with 200 ml of toluene, and then the organic layer was mixed, concentrated and dried under reduced pressure to obtain 13.0 g of a crude product. After treatment with activated carbon, crystallization with ethyl acetate / hexane solvent gave 3.85 g (0.00536 mol, yield 48.7%) of 2,7-bis (N-9-phenanthryl-N-phenylamino) dibenzodioxin. It was. The purity of the obtained product was 98.6 area% (H PLC, 254 nm). Further sublimation purification was performed. FD-MS, m / z 718 [M] +, mp not observed. Tg 149 ° C.

Example 6
Synthesis of 2,7-bis (9-carbazolyl) thianthrene (compound 27) In a solution of 0.7 g (3.1 mmol) of palladium (II) acetate in xylene (40 ml), 3 ml (12.4 mmol) of tri tert-butylphosphine was added. In addition, the mixture was stirred with heating at 80 ° C. for 30 min. This solution was heated to 80 ° C with 2,7-diaminothianthrene 6.5 g (0.0264 mol), 2,2'-dibromobiphenyl 20.5 g (0.0657 mol) and tert-butoxy sodium 22.0 g (0.229 mol) xylene ( 380 ml) was fed into the solution. Thereafter, the temperature was raised to 125 ° C., and the mixture was heated and stirred at the same temperature for 5 hours. After cooling to room temperature, 200 ml of water was added. The precipitate was collected by filtration and washed with THF to obtain 5.18 g (0.0095 mol, yield 36%) of 2,7-bis (9-carbazolyl) thianthrene. The purity of the obtained product was 99.1 area% (H PLC, 254 nm). Further sublimation purification was performed. APCI-TOFMS, m / z 547 [M + H] +, mp 350 ° C, Tg 137 ° C.

Example 7
In FIG. 1, an organic EL element having a configuration in which the hole injection layer is omitted and an electron injection layer is added is prepared. Each thin film was laminated at a vacuum degree of 4.0 × 10 −4 Pa by a vacuum deposition method on a glass substrate on which an anode made of ITO having a thickness of 150 nm was formed. First, NPB was formed to a thickness of 60 nm on ITO as a hole transport layer.
Next, on the hole transport layer, Compound 12 and Ir (ppy) 3 as a light emitting layer were co-evaporated from different vapor deposition sources to form a thickness of 25 nm. The concentration of Ir (ppy) 3 was 7.0%. Next, Alq3 was formed to a thickness of 50 nm as an electron transport layer. Further, lithium fluoride (LiF) was formed to a thickness of 0.5 nm as an electron injection layer on the electron transport layer. Finally, on the electron injection layer, aluminum (Al) was formed as an electrode to a thickness of 170 nm, and an organic EL element was produced.

  When an external power source was connected to the obtained organic EL element and a DC voltage was applied, it was confirmed that the organic EL element had the light emission characteristics as shown in Table 5. In Table 5, the luminance, voltage, and luminous efficiency show values at 10 mA / cm2. The maximum wavelength of the device emission spectrum was 517 nm, indicating that light emission from Ir (ppy) 3 was obtained.

Example 8
An organic EL device was produced in the same manner as in Example 7 except that Compound 3 was used as the main component of the light emitting layer. Table 5 shows the light emission characteristics.

Example 9
An organic EL device was produced in the same manner as in Example 7 except that Compound 1 was used as the hole transport layer and TAZ was used as the main component of the light emitting layer. Table 5 shows the light emission characteristics.

Example 10
An organic EL device was prepared in the same manner as in Example 7 except that Compound 27 was used as the main component of the light emitting layer. Table 5 shows the light emission characteristics.

Comparative Example 1
An organic EL device was produced in the same manner as in Example 7 except that HMTPD was used as the hole transport layer and TAZ was used as the main component of the light emitting layer. Table 5 shows the light emission characteristics.

Comparative Example 2
An organic EL device was produced in the same manner as in Example 7 except that TAZ was used as the main component of the light emitting layer. Table 5 shows the light emission characteristics.

Example 11
In FIG. 1, an organic EL element having a configuration in which an electron transport layer was omitted and an electron injection layer was added was prepared. A hole transport layer is formed by forming CuPC with a thickness of 25 nm on the ITO layer of the glass substrate with ITO under a vacuum degree of 7 to 9 × 10 −5 Pa, and forming a compound 8 with a thickness of 45 nm thereon. Got. A light emitting layer was obtained by forming Alq3 as a light emitting material with a film thickness of 60 nm thereon. Further thereon, 6F of LiF and 170nm of Al were deposited to form a cathode.
When an external power source was connected to the obtained electroluminescent elements and a DC voltage was applied, it was confirmed that these electroluminescent elements had the light emission characteristics as shown in Table 6. Green light emission was obtained from all these devices. The emission peak wavelength was 500 nm, and it was confirmed that the emission was from Alq3 alone.

Example 12
An electroluminescent device was produced in the same manner as in Example 11 except that Compound 9 was used to form the hole transport layer. Table 6 shows the light emission characteristics.

Comparative Example 3
An electroluminescent device was produced in the same manner as in Example 11 except that NPB was used to form the hole transport layer. Table 6 shows the light emission characteristics.

Industrial applicability

  Since the heterocyclic compound of the present invention exhibits high charge (electron / hole) transfer characteristics, it can be driven at a low voltage when applied to an organic EL device. Further, when used as a light emitting host material, electrons and holes move in a balanced manner, a wide light emitting region is formed, and high efficiency is achieved. Furthermore, since it has a high triplet energy that is important in phosphorescent light-emitting devices, when used as a light-emitting host material or charge transport material of phosphorescent devices, efficient energy confinement of the phosphorescent dopant triplet excited state is achieved. It becomes possible, and highly efficient phosphorescence emission from a dopant is obtained. In addition to these good electrical properties, the heterocyclic compounds have stable thin film stability. The organic EL element containing the heterocyclic compound of the present invention in the organic layer exhibits high luminance and high efficiency light emission characteristics at a low voltage, and is excellent in durability. Therefore, the flat panel display (for example, for OA computers or Wall-mounted televisions), in-vehicle display elements, mobile phone displays, light sources that make use of the characteristics of surface light emitters (for example, light sources for copiers, backlight sources for liquid crystal displays and instruments), display boards, indicator lights, etc. Application spreads.

Claims (5)

The organic electroluminescent element which has an organic layer containing the heterocyclic compound represented by the following general formula (II) or the following general formula (III).

In the general formulas (II) and (III), —NAr ₁ Ar ₂ and —NAr ₃ Ar ₄ are independently unsubstituted, a lower alkyl group, a lower alkoxy group, an aryl group having 4 to 10 carbon atoms, or a carbon number of 4 to A substituted N-carbazolyl group substituted with 10 aryloxy groups. However, the case where the substitution positions of -NAr ₁ Ar ₂ and -NAr ₃ Ar ₄ are the _2nd and 8th positions is excluded. The aryl group means an aromatic hydrocarbon group and a heterocyclic aromatic group. m and n each independently represent 1 or 2. The organic electroluminescent element according to claim 1, comprising a heterocyclic compound in which m and n are 1 in the general formula (II) or the general formula (III). The organic layer containing the heterocyclic compound represented by the general formula (II) or the following general formula (III) is at least one layer selected from the group consisting of a light emitting layer, a hole transport layer and a hole injection layer. Item 3. The organic electroluminescent device according to Item 1 or 2. The organic electroluminescent element according to claim 3, wherein the organic layer containing the heterocyclic compound is a light emitting layer further containing a phosphorescent dopant. The organic electroluminescent element according to claim 3, wherein the organic layer containing a heterocyclic compound is a hole transport layer.

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